EtronTech
EM636327
registered coincident with the Block Write command is used to mask specific column/byte
combinations within the block. The mapping of the DQ inputs to the column/byte combinations is
shown in following table.
The overall Block Write mask consists of a combination of the DQM inputs, the Mask register,
and the column/byte mask information, as shown in the following figure. The DQM and Mask
register masking operates normally as for a Write command, with the exception that the mask
information is applied simultaneously to all eight columns. Therefore, in a Block Write, a given bit is
written only if a "0" is registered for the corresponding DQM input, a "1" is registered for the
corresponding DQ signal, and the corresponding bit in the Mask register is "1".
Block of Columns
(selected by A3-A7 registered
coincident with Block Write command)
Row in Bank
(selected by A0-A9,
and BS registered
coincident with BankActivate
Command)
Column Mask DQ0
on the DQ DQ1
inputs DQ2
DQ3
(registered
DQ4
coincident
DQ5
with Block DQ6
Write Command DQ7
DSF
BankActivate
command
D Q
CK
DQM0
MR0
MR 1
Mask Register
(previously loaded
from corresponding
DQ inputs)
MR2
MR3
MR4
MR5
MR6
MR7
CR0
CR 1
CR2
CR3
CR4
CR5
CR6
CR7
Note:
Only the lower byte is shown. The operation is identical for other bytes.
Block-Write Masking Block Diagram
Preliminary
12
December
1998
ETRON [ ETRON TECHNOLOGY, INC. ]
